There are a number of solutions for impact and crush protection. For example, those used in roll over protection for vehicles; these can be broken loosely into two categories, rigid and active.
However, most roll over protection bars are rigid (even those that are active) and therefore could injure a rider or passenger of the vehicle if the roll over bar struck them while the vehicle is rolling, for example midroll or when they are on the ground. This is even more likely if the user or passenger is pinned between the roll over protection bar and the ground. The impact energy, or at least some of it, is transferred into the user. Thus while the user may be protected from the weight of the vehicle landing on them, some or all of that weight or kinetic energy may still be transferred to the user if they are struck or pinned by the roll over protection bar.
Rigid roll over protection bars are perhaps the oldest and most well known. They typically are a bar or hoop that extends from the vehicle and in the event of a roll over will prevent the vehicle impacting onto the user. In some situations these may also prevent the vehicle from rolling further. These come in either vertical or horizontal configurations.
Examples of such bars are shown for example in the patent family of EP2073998, NZ 575562, & AU2007294463 for a roll over protection system. These documents disclose a narrow elongate steel or similar material bar that extends upwardly from the rear of the vehicle, such as an all terrain vehicle.
The bar is rigid and is not designed to flex on impact. The geometry of such a narrow long shape bar ensures the vehicle cannot roll onto its back, or if it does, then it rolls onto its side again. However, the bar disclosed would injure a person if they were underneath it.
Also the bar disclosed would cause the vehicle to continue rolling onto its side and thus may injure the person.
A variation of rigid roll over bars is the deformable roll over protection bar. Examples of such a bar are shown in U.S. Pat. No. 5,890,738 for a rollover bar with deformable bearing. This document discloses a roll bar for a vehicle that is rigid and is mounted to a rigid part of the vehicle but has an elastically deformable part between it and the vehicle mount. This allows some movement of the roll bar (for example on impact of a user's head) to reduce injury before the roll bar is rigidly prevented from further movement. The bar disclosed would injure a person if they were underneath it.
Further examples are those shown in WO00/18678 and GB01341540 which are for a Industrial vehicle overhead guard and protective roof for a working vehicle respectively. These documents disclose an overhead protection roof for vehicles, such as a forklift, to guard the user from overhead falling debris. The roof is made of multiple elements, which are mounted off an overhead member. The elements are rigid to deflect debris falling from overhead but can move if the vehicle rolls over and the user is trapped between an object (for example the ground) and the roof elements.
Thus the user has a reduced chance of injury in a roll over situation where otherwise they would be pinned and injured by the roof.
Examples of active roll over protection systems are shown in US2009/0267335 for an ATV roll bar system. This document shows a rigid space frame that extends upward from a vehicle, such as an ATV. The space frame has a seatbelt or similar harness for the user, and has a mesh to provide a backrest for the user against the space frame.
The roll bar system may also have a tilt sensor that will set off an alert to the user of a near roll event and may also extend roll over stop bars.
However whilst active the roll bar is still rigid. The bar disclosed would injure a person if they were underneath it.
US2009/0278342 is for a vehicle roll bar apparatus with active material actuation. This document discloses a roll over bar that is stowed within the vehicle. When a roll over event is detected by sensors the roll over bar is deployed to at least protect the occupants from being crushed under the weight of the vehicle.
The user would be strapped into the vehicle and so is unlikely to be thrown clear under the roll bar. The roll bar is rigid. The bar disclosed would injure a person if they were underneath it.
In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.
It is an object of the present invention to provide an improved impact protection system or to overcome the above shortcomings or address the above desiderata, or to at least provide the public with a useful choice.